A power supply apparatus employs a unidirectional unit equipped with a diode, a bypass switch connected in parallel to the diode, and a controller which turns the bypass switch ON when a forward voltage appears in the diode in order to rectify or prevent the backflow of the power from a power generating unit built in portable electronic equipment of an arm-worn type or the like; it is able to eliminate almost all loss caused by the forward voltage at the time of power supply. The elctromotive force of the power generating unit incorporated in arm-worn type electronic equipment ranges from almost the same level to about a few times the level of the forward voltage; hence, the use of the unidirectional unit enables rectifying efficiency to be markedly improved.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A power supply apparatus for supplying power to a portable electronic equipment having a processing unit, comprising: a charging unit coupled to the processing unit; an AC power generating unit for generating an AC electrical signal and coupled to said charging unit; and a supply section coupled to said AC power generating unit and having at least one unidirectional unit for full-wave rectifying of said AC electrical signal generated by said AC power generating unit; said at least one unidirectional unit having a diode, a bypass switch having an ON state and connected in parallel to said diode, and a controller for turning said bypass switch ON when a forward voltage appears across said diode, wherein said controller compares the voltage at both ends of said diode; wherein said supply section supplies power from said AC power generating unit to one of either said charging unit or the processing unit via said at least one unidirectional unit.
2. The power supply apparatus according to claim 1 , wherein said bypass switch is a field-effect transistor and said diode of said at least one unidirectional unit is a parasitic diode of said field-effect transistor.
3. The power supply apparatus according to claim 1 , wherein said AC power generating unit outputs an output voltage and said controller is adapted to control said bypass switch at a voltage higher than said AC output voltage of said power generating unit.
4. The power supply apparatus according to claim 1 , wherein said bypass switch has an OFF state and said controller turns said bypass switch OFF after a predetermined time has elapsed since said controller has turned said bypass switch to said ON state.
5. The power supply apparatus according to claim 1 , wherein said diode has a first end and a second end and a first voltage measured at said first end and a second voltage measured at said second end and said controller has a comparator for comparing said first voltage and said second voltage.
6. The power supply apparatus according to claim 5 , wherein said comparator has a detection voltage hysteresis.
7. The power supply apparatus according to claim 1 , wherein said bypass switch is an enhancement type field-effect transistor.
8. The power supply apparatus according to claim 7 , wherein said diode is a parasitic diode of said field-effect transistor.
9. The power supply apparatus according to claim 1 , wherein said power generating unit generates AC power, and said supply section rectifies the AC power via said at least one unidirectional unit and supplies the rectified AC power to at least one of either the charging unit or the processing unit.
10. The power supply apparatus according to claim 9 , wherein said supply section has a first input terminal and a second input terminal, said first input terminal and said second input terminal connected to said AC power generating unit; a first output terminal and a second output terminal, said first output terminal and said second output terminal connected to at least one of either said charging unit or the processing unit; a second unidirectional unit, said at least one unidirectional unit being connected to said first input terminal and said second unidirectional unit being connected to said second input terminal, said at least one unidirectional unit and said second unidirectional unit sharing said first output terminal; and a first field-effect transistor and a second field-effect transistor, said first field-effect transistor being connected to said first input terminal and said second field-effect transistor being connected to said second input terminal, said first field-effect transistor and said second field-effect transistor sharing said second output terminal.
11. The power supply apparatus according to claim 10 , wherein said second unidirectional unit has a bypass switch and said bypass switch of said at least one unidirectional unit and said bypass switch of said second unidirectional unit are of a first conductive type field-effect transistor having a parasitic diode; said diode of said at least one unidirectional unit being the parasitic diode of said first conductive type field-effect transistor; said first field-effect transistor and said second field-effect transistor being of a second conductive type each having a gate input; and a first voltage at said first input terminal and a second voltage at said second input terminal wherein the voltage at said second input terminal is applied to the gate input of said first field-effect transistor, and the voltage at said first input terminal is applied to the gate input of said second field-effect transistor.
12. The power supply apparatus according to claim 11 , wherein a first resistance load element is connected to the gate input of said first field-effect transistor and a second resistance load element is connected to the gate input of said second field-effect transistor.
13. The power supply apparatus according to claim 11 , wherein said controller of said at least one unidirectional unit and said second unidirectional unit has a 3-input comparator for comparing the voltages at said first input terminal and second input terminal with the voltage at said first output terminal, said first output terminal being common to said at least one unidirectional unit and second unidirectional unit.
14. The power supply apparatus according to claim 1 , wherein said AC power generating unit generates AC power, and said at least one unidirectional unit of said supply section prevents backflow from the charging unit and the processing unit to said power generating unit.
15. Portable electronic equipment comprising: a power supply apparatus comprising: an AC power generating unit for generating an AC signal; a charging unit coupled to said AC power generating unit for accumulating DC power supplied from said AC power generating unit; and a supply section coupled to said AC power generating unit and having at least one unidirectional unit for full-wave rectifying of said AC signal generated by said AC power generating unit; said at least one unidirectional unit having a diode, a bypass switch having an ON state and connected in parallel to said diode, and a controller for turning said bypass switch ON when a forward voltage appears across said diode; and a processing unit coupled to said charging unit, said processing unit using the DC power supplied from said AC power generating unit; and wherein said supply section supplies power from said AC power generating unit to one of either said charging unit or the processing unit via said at least one unidirectional unit.
16. A power supply apparatus for supplying power to portable electronic equipment having a processing unit, comprising: a charging unit coupled to the processing unit; an AC signal generating unit for generating an AC signal and coupled to said charging unit; a supply section coupled to said AC signal generating unit and having two unidirectional units to full-wave rectify said AC signal generated by said AC signal generating unit; each of said two unidirectional units having a diode, a field-effect transistor connected in parallel to said diode, and a comparator for comparing a voltage present across said diode and for turning said transistor on when a forward voltage is present across said diode; and said supply section supplying power from said AC signal generating unit to one of said charging unit or said processing unit via said two unidirectional units.
17. The power supply apparatus according to claim 16 , wherein said diode is a parasitic diode of said field-effect transistor.
18. The power supply apparatus according to claim 16 , wherein; said AC signal generating unit has a first output terminal and a second output terminal; a first one of said two unidirectional units is connected between said first output terminal and a first line of said charging unit; a second one of two said unidirectional units is connected between said second output terminal and said first line of said charging unit; a first field-effect transistor is connected between said first output terminal and said second line of said charging unit; a second field-effect transistor is connected between said second output terminal and said second line of said charging unit; and wherein said supply section further comprises a full-wave rectifier bridge circuit constructed by said first said unidirectional unit, said second unidirectional unit, said first field-effect transistor and said second field-effect transistor, and supplies power from said AC signal generating unit to one of said charging unit or said processing unit connected between said first line and said second line.
19. A power supply apparatus for supplying power to a portable electronic equipment having a processing unit, comprising: a charging unit coupled to the processing unit; an AC power generating unit for generating an AC signal and having a first output terminal and a second output terminal; two unidirectional units for full-wave rectifying said AC signal generated by said AC power generating unit; each of said two unidirectional units having a diode, a field-effect transistor connected in parallel to said diode, and a comparator for comparing a voltage present across said diode and for turning said transistor on when a forward voltage is across said diode, an accumulator having a first terminal connected to said first output terminal of said AC power generating unit; a voltage-boosting rectifier circuit comprised of said accumulator and said two unidirectional units; a first one of said two unidirectional units being connected between a second terminal of said accumulator and said second terminal of AC power generating unit; a second one of said two unidirectional units being connected to said second terminal of said accumulator; and said voltage-boosting rectifier circuit supplying power from said AC power generating unit to one of said charging unit or the processing unit.
20. The power supply apparatus according to claim 16 or 19 , further comprising a voltage-boosting circuit for boosting a voltage accumulated in said charging unit and wherein said comparator or said processing unit is driven by a boosted voltage by said voltage-boosting circuit.
21. The power supply apparatus according to claim 16 or 19 , wherein said comparator turns said field-effect transistor off after a predetermined time has elapsed after said comparator has turned said transistor on.
22. The power supply apparatus according to claim 16 or 19 , wherein said comparator has a detection voltage hysteresis.
23. The power supply apparatus according to claim 16 or 19 , wherein said comparator has three input terminals.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
January 26, 1999
July 16, 2002
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